Brace and bit therefor



J. V! JANIN.

BRAGE AND BIT THEREFOR. APPucAfmN FILED Aum. I920,

1,428,099. 'latentedseptl 551922.

JOE-IN "V'. JANIN, OF SEATTLE, WASHINGTON.

BRACE AND BIT THEREFOR.

Application filed August 5, 1920. Serial No. 401,458.

To all whom it may concern.

Be it known that 1, JOHN V. JANIN, a citizen of the United States ofvAmerica, and resident of the city of Seattle, in the county of King andState of Vashington, have invent-ed certain new and useful Improvementsin Braces and Bits Therefor, of which the following is a specification.

My invention relates to chucks which are intended for such tools asbraces of the kind commonly used by carpenters.-

The object of my invention is to produce a chuck for such a bracehavingnnprove ments in its construction which will facilitate itsoperation and cheapen the cost of manufacture thereof, while at the sametime making a strong, durable and reliable tool.

Further objects of my invention will be seen from a study of thefollowing descrip tion and the accompanying drawings.

lily invention consists of the novel parts and combinations of partswhich will be particularly defined in the claims.

In the accompanying drawings I have shown the construction of my chuckin its preferred form.

Figure 1 shows a brace, the chuck constituting my invention being shownin longitudinal section.

Figure 2 is a partial section and partial elevation of a detail of thechuck.

Figure 3 is a cross section taken upon the plane indicated by the line83 of Figure 1.

The bit-holder or chuck has a base or central frame member, which hasahead 1, this being slotted len thwise upon an axial plane, leaving twofingers 10, which fingers have their outer surfaces threaded, as isclearly shown in Figures 1 and 2. This head has an integral tubularshank 11 which carries its part of two rotative bearings, whichbearings, as illustrated, are ball bearings.

\Vithin the slot in the head 1 are placed two bit-clamping levers 2.These are pivoted close to their-inner ends, to swing about pivotcenters which are located well outwardly from the main axis of thebit-holders. As illustrated, the inner ends of these levers are providedat their inner sides, with convex rounded surfaces 20, and the outersides with correspondingly concave rounded surfaces 21, the two surfaces20 and 21 being concentric, or arcs of circles struck from the samecenter, which center is the pivot center upon which they swing.

The two inner, convexly rounded surfaces 20, which are upon the innerside faces of the bit-clamping levers2, are in contact with each other.These inner ends of the levers are held against separating by means of aretaining ring 22, clamped between a shoul der 18 of the head 1 and acollar 12 threaded upon the shank 11, and which has its inner surfacecurved to fit the rounding surface 21 of the two clamping levers. Inthis manner a pivotal support is provided for the bit clamping levers 2,which has its pivot center well outward from the axis of the bit-holder.

On the inner face of each of the bit clamping levers 2, near to, butslightly removed from their inner ends, are formed bit-engaging andholding surfaces, or recesses 23. The levers are recessed at this pointso as to engage with a suitably formed tip 30 of the bit 3. The shank ofthe bit 3 at its inner end is provided with a tip 30, which hasflattened side surfaces, or surfaces of any suitable character which arenot surfaces of rotation, and the recesses 23, in the inner end sidefaces of the bit-clamping levers 2, are shaped to lit the side surfacesof the tip of the bit.

Preferably, this tip section 30 has the outer or end portion thereofslightly thicker than its inward portion, so that when engaged by theforcing together of the levers 2 it will not only prevent the bit fromturning, but will positively grip and hold it against relative movementlengthwise of the bit, so that an outward pull upon the brace, while itis holding the bit, will not cause the brace to pull off from or releasethe bit.

Screwing upon the outer surface of the head 1 is the clamping sleeve 4.This sleeve has an inner tapered or conical surface 40, which is adaptedto engage the outer end of the bit-clamping levers 2 to force themtogether when the sleeve is screwed down upon the head. As the pointwhere the levers 2 engage the bit to hold it is quite close to the pivotaxes upon which they swing, and the outer ends ofthese levers are aconsiderable distance therefrom, the gripping action upon the bit isvery powerful. The swinging ends of the levers 2 are well within theopen end of the sleeve 4, to leave its bit-receiving opening of maximumwidth.

The hole in the outer end of the sleeve 4, through which the bit isinserted, must be made large enough to accommodate the maximum sizes ofbit shanks suited for use in the brace. Many of the bits which it wouldbe desired to use do not require so large a shank. As I desire to employthe outer end of this sleeve as a support for the bit, I prefer tosupply the smaller sizes of bits, or those having smaller shanks, withprojecting wings, as 31, which have their outer surfaces correspondingwith the outer surface of a cylinder, which would snugly fit the hole inthe sleeve. These are located at ust 'the right distance from the end ofthe bit shank so that when the shank is secured in place, these wingswill lie in the opening at the outer end of the sleeve 4. These wingsmay be provided entirely outside of the normal circular outline of theshank, or they may be formed in any suitable manner.

The shank 11 may be suitably mounted in a casing 50 secured upon thebrace frame 5, as in ball bearings 51 and 52, for instance. The shank isshown as secured in place by means of a bolt 15 threading therein. Theexact manner of mounting and securing the chuck in place, and the mannerof controlling the direction of its rotation, form no part of my presentinvention, and may be accomplished in any manner found suitable ordesirable. I shall not, therefore, describe such parts, as they may besuch as are ordinarily found in similar tools.

Between the inner end of the bolt 15 and the inner ends of the bitclamping levers 2 is placed a spring 16, which acts upon the inner endsof the bit-clamping levers 2 so as to separate their outer ends. Asillustrated, this is done through the medium of a small follower 17,which is placed between the spring and the ends of the levers.

The means employed for securing and holding the bit has a powerful gripthereupon, due to the relative length of the parts of the clampinglevers 2. The construction of these parts is also such as will grip andsecurely hold the bit against an outward pull. The tip 30 of the bit,which is en gaged by the levers 2, is some distance from the wings 31,at which point the shank of the bit is supported against lateralmovement. In consequence, the bit is very securely held against lateraldeflection.

While I have described the bit-holding chuck only in connection with acarpenters hand brace, it is evident that it may be employed with othersimilar tools, as, for instance, abreast drill.

What I claim as my invention is:

1. A bit holder for braces having two clamping levers pivoted at theirinner ends 1,4.2s,oee

and provided upon their opposed faces adjacent their pivoted ends withfiat bit holding surfaces, and a sleeve embracing and ljustablelengthwise of said levers and having cam surfaces engageable with theends of the clamping levers opposite to their pivots, said sleeve havingat its outer end and spaced from said bit-holding surfaces of theclamping levers, surfaces adapted for sup porting engagement with thebits placed therein.

2. A bit holder for braces comprising a body axially slotted andexternally threaded, bit clamping levers fitting within said slot withtheir inner ends provided both at their inner and outer sides withpivoting surfaces permitting said levers to swing in their holding slot,a fulcrum and retaining ring surrounding the slotted body and engagingthe external pivoting surfaces of said clamping levers, a clampingsleeve screwing upon said body and having an internal inclined surfaceengaging the outer ends of the bit clamping levers to swing them towardsthe central axis of the holder.

A bit holder for braces comprising a body axially slotted and externallythreaded, bit clamping levers fitting within said slot with their innerends provided both at their inner and outer sides with outwardlyconcaved pivoting surfaces permitting said levers to swing in theirholding slot, said levers having bit clamping recesses upon their innerfaces spaced outward from their pivot ends, a fulcrum and retaining ringsurrounding the slotted body and engaging the external pivoting surfacesof said clamping levers, a clamping sleeve screwing upon said body andhaving an internal inclined surace engaging the outer ends of the bitclamping levers to swing them towards the central axis of the holder.

l. In a bit holder for braces, two clamping levers having their innerends connected to permit their outer ends to be separated or broughttogether, said levers being formed to grip between them a bit, and asleeve embracing and adjustable lengthwise of said levers and having camsurfaces engageable with the outer ends of the clamping levers, saidsleeve having at its outer end and spaced from the gripping portions ofsaid levers, surfaces adapted for supporting engagement with the bitsplaced therein.

Signed at Seattle, King County, Washington, this 30th day of July, 1920.

JOHN V. JANIN.

